α-MoO3@SiO2 core-shell nanospheres: spatially confined synthesis and tribological properties

Abstract

Molybdenum disulfide (MoS2) is widely used in the field of lubrication due to its unique layered structure. But in a high temperature environment, MoS2 can be greatly deteriorated by severe oxidation, showing a higher friction coefficient and a shorter service life. The modified Stöber method was used to coat SiO2 on the surface of MoS2, so that MoS2 was converted into layered α-MoO3 in a confined space at high temperature. The morphology, size and composition of the prepared α-MoO3@SiO2 core-shell nanoparticles were investigated using transmission electron microscopy, scanning electron microscopy, x-ray diffraction and Raman spectroscopy. The tribological properties of the prepared nanoparticles were investigated by ball-disk friction experiments. The results show that the prepared nanoparticles have uniform particle size, high shell coverage and excellent anti-wear properties. Based on the analysis of the wear scars and the existing elements on the friction surface, the lubrication mechanism of the core-shell structure in the friction experiment was discussed.